1. Field of the Invention
The present invention relates to an image forming apparatus that displays guidance information related to an operation of the apparatus for supporting a user, in a sleep mode (hereinafter also referred to as “power saving mode”).
2. Description of the Background Art
Electronic paper is a thin display technology similar to a liquid crystal display and the like. The electronic paper is characterized in that it has similar appearance as ordinary paper, that displayed contents are electrically rewritable, and that power consumption thereof is very low as electric power is unnecessary to retain the displayed contents. Further, electronic paper is non-volatile, that is, once the displayed contents are rewritten, the displayed contents are maintained even when power is turned off. Attempts to apply electronic paper as such have been made in various technical fields.
By way of example, Japanese Patent Laying-Open No. 2003-209718 (hereinafter denoted as “'718 application”) proposes a technique of utilizing electronic paper in a digital camera. According to the technique disclosed in '718 application, when a power button is pressed by a user while the power is on, remaining battery level is calculated, and the maximum number of pictures that can be taken is calculated from available memory space. These pieces of calculated information are output to electronic paper, and on the electronic paper, information related to the remaining battery level and the maximum number of pictures that can be taken at present is displayed. Even when the power of digital camera is turned off thereafter, the displayed contents of information related to the remaining battery level and the maximum number of pictures that can be taken before power-off are maintained.
Further, Japanese Patent Laying-Open No. 2006-201460 (hereinafter denoted as “'460 application”) proposes a technique of utilizing electronic paper in an image forming apparatus such as a multifunctional printer. According to the technique disclosed in '460 application, information related to image formation, such as counter information and information of supplies, is displayed on electronic paper. This allows collection of necessary pieces of information without turning on the power.
Recently, in consideration of global environment including global warming, a large number of devices that make transition to sleep mode to limit power consumption comes to be heavily marketed. Such trend is also felt in the field of image forming apparatuses including multifunctional peripherals.
In designing an image forming apparatus, guidance information for supporting a user may be displayed, by maintaining the contents that have been displayed on the display device on electronic paper, when the display device goes dark in sleep mode.
Though it is possible by the techniques described in '718 and '460 applications to transmit necessary information to the user or service person even when power is off by displaying information before power off on the electronic paper, the idea described above cannot be realized. Specifically, the techniques described in '718 and '460 applications cannot directly be adopted to realize the idea described above.